Concrete floor



GJC. WEBB AND T. T. POTTENGER. CONCRETE FLOOR.

APPLICATION FILED MAR. 2. 1917.

1,348,610, PZL'E6I lt6dA1lg.3,1920.

' i INVENTORS 1 7 1044a We ,srA E' PATENT OFFICE-Q] GEORGE opwnnn ANDEI-IOMAS TLPOTTENGER, or rirrsnuncrn, rENNsYLvAivInQ ooironn rn rnoon.

Y Y l Application filed March 2,

T0 at whom it may concern: I

Be it known that we, GEORGE C. WEBB and THoMAs T. POTTENGER, citizens of the United States, and residing in the city of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented or discovered new and useful Improvements n Concrete Floors, of which the followlng 1s a specification.

Our invention relates to the method of forming a smooth, wear-resisting surface on a concrete slab or floor which is composed of coarse aggregate, without the application of a top coat of finer aggregate than that which composes the mass of the slab. Our method may be practised when floors are laid directly on the ground, or when the floors are laid above the ground, such as of reinforced concrete construction or combination hollow tile and concrete.

The figure is a View showing a floor slab as laid in accordance with our present method and which it is designed to treat as hereinafter described.

The purpose of our present invention is to overcome the objections incident to the usual practice of forming what is known as a two course floor, and the same is as follows.

The rough concrete slab is poured and brought to substantiallythe final grade by what is known in the art as screeding and V rodding. As soon as it has set sufficiently,

the slab is wood floated to a substantially uniform level. This operation pushes the coarse gravel down and brings the finer particles of the aggregate to the surface, thus giving a relatively smooth top surface.

The slab is then allowed to set and the work of erecting the forms of the succeeding floor or floors may be proceeded with.

Each floor slab is prepared in a similar manner, and, after the forms have been re moved and the dirt and debris cleared from the floor, the surface of the slab is ground with stones or grinding mechanism, using an abrasive material, such as sand, to substantially as smooth a surface as that contemplated for a hard troweled top coat. This produces a fioor without expansion joints, which is a great advantage, as in many instances disintegration starts at such joints. We then prefer to continue the grinding but substitute for the abrasive material a cream like grout of cement and water to build up the surface and to fill Specification. of Letters Patent, I I Patentefl.

I917. Serial No. 151,879; 1

uneven spots or depressions. After the t grout has been Well-ground into-the surface of the slab,-the excess grout 'is removedand the floor permitted to dry. After the fioor is dry, we prefer as an additional step, to treat the surface with what is known as a hardener, the composition of which varies, but which consists, generally speaking, of a water solution of silicates, fiuor silicates or sulfates. The generally accepted theory is that this hardener forms, with the free calcium contained in the concrete, hard and insoluble calcium salts which fill the pores of the surface of the floor, thus making the same more resistant to abrasion and dusting, and ren-,

dering it more impermeable to liquids. For the grinding operations we prefer to use a rotary grinding machine.

The figure illustrates diagrammatically a slab poured according to the present invention and before it is wood floated. That is, said figure illustrates the fioor slab as consisting of a more or less homogeneous mass without the relatively loosely attached topping which has formed the upper surface of floors as heretofore constructed. The variation from the present method of pouring a slab is that in our method the screeds are placed and the floors are rodded off to the proper grade and wood floated, as described. This is not a complicated or time consuming operation, and its cost is so slight as to be practically negligible.

Among the advantages of our improved method may be mentioned the following. It does away with the top coat, thus removing from the fioor an element which is particularly subject to disintegration and separation from the slab, and also eliminates an element which is figured as a dead load at approximately twelve pounds per square foot while adding no structural value to the slab. Aside from the feature just mentioned, the absence of the topping is advantageous, as it is thus possible to start the grinding of the floors while the shoring is still under the beams and in most instances the surfacing may be completed by the time when it would be proper to start the pouring of the top coat or topping under the old practice;

Another advantage in building operation is that after the forms are taken down and the surfacing is in progress, other mechanics or workmen can continue their work without hindrance, as only a relatively small part of the floors are occupied While the surfacing is being done- Under the" old method, thefloor could not be used for at least four or five days after the topping for the purpose described.

What We desire to claim is I The method of forming a wearing surface for concrete floors wh'ich consists in grindingthe surface of the floor first in the presence of abrasive materials and second in the presence of a grout of cement and ater,

"igned: at Pittsburgh, of February, 1917.

GEORGE WEBBI THoMAs '1. POTTENGER.

Pa., this 28th day 

